-LRB- CNN -RRB- -- When video of Justin Bieber 's deposition surfaced this week and went viral , most of us were amusedâ $ '' especially lawyers . -LRB- You can watch some of it here -RRB- . As he answers questions for a battery case involving his bodyguard and a photographer , Bieber is glib and tries to parry the deposing attorney 's questions . If we could see off camera , we might see Bieber 's attorney subtly shaking his head in frustration . Counsel would know what Justin may not want to `` beliebe '' : You only hurt yourself at a deposition when you bicker with the questioning attorney .

To those luckily unfamiliar with depositions , it may have looked simply like Bieber was being a defiant celebrity in an interview . But a deposition is no interview , and treating it that way is to invite catastrophe . Bieber made a number of missteps typical for beginners . Here 's what he should have known :

What is a deposition ? Testifying at a deposition looks a little like testifying at a trial . There are lawyers , a stenographer , questions and answers . But a deposition is not a trial . At trial , you can tell your story and convince a jury of your position . A deposition , on the other hand , is the other side 's only opportunity to find out what 's in your mind , lock your story in writing , and have it ready to bash you over the head with if you testify inconsistently at trial . Generally , the more your opponent gets you to talk at a deposition , the more information he or she has to use against you at trial . An argumentative witness like Bieber is a dream come true for his opponent .

Smile , you 're on camera : Most depositions are not videotaped . It 's expensive and the costs do n't always justify the benefits . But Justin Bieber 's opponents want him on camera , preferably preening and pugnacious . Watch , for example , when he answers : `` Guess what ? Guess what ? I do n't recall . '' Had the deposition only been recorded in a transcript , on paper that looks pretty innocent . But watch the oozing hostility on the video , and his dramatic `` I do n't recall '' might play to a jury as `` I am conveniently forgetting negative evidence . '' His opponent scored points deposing him on camera .

You ca n't answer if you do n't know the question : Bieber can be seen interrupting questions to answer . A witness should always wait until the question has been completely asked . First , someone is typing the questions and answers into a transcript , and interruptions end up looking like someone spilled Scrabble letters onto a piece of paper : Unintelligible . A witness should only answer the question asked , lest he volunteer information to help the other side . And , if a question has n't even been finished yet , a witness ca n't possibly limit the answer to the question asked -- he does n't know what the question is yet ! Best practice ? Wait until the question is complete ; pause and ask yourself if you understand the question ; if you do , ask yourself if you know the answer to the question ; if you do , only answer the question asked .

Depositions are not soapboxes : At a deposition , you will never `` show up '' the other side 's lawyers . You are not there to show them the error of their ways and win them over . They will not turn to colleagues and announce : `` You know what ? After hearing this story , I think we 're on the wrong side of justice here . We should pack up and go home . Thanks for your time , Mr. Bieber . ''

Objection to the objection : Bieber can be heard warning the lawyer not to ask about sensitive subjects , like his possible relationship with other celebrities . Elsewhere , he actually -LRB- and hilariously -RRB- interposes his own `` objection . '' At a deposition , the lawyer asks the questions , not the witness .

The witness does n't decide what 's relevant . At a deposition , `` relevant '' subject matter is any question `` reasonably calculated to lead to the discovery of admissible evidence . '' It does n't have to be admissible evidence , just calculated to possibly lead to admissible evidence .

Therefore , virtually any question is arguably proper . That 's why grizzled veterans of `` deps '' routinely acknowledge that , practically , they can feel like a fishing expedition . Bieber may not like the questions , but he takes his chances with the judge if he refuses to answer .

Arguing requires additional words : Do n't argue with the lawyer , Justin . The rules of evidence are always skewed in favor of the attorney , and against the witness . Witnesses are often smarter than the lawyer , but the rules simply give the lawyer an overwhelming advantage . Moreover , arguing takes more words than simply answering yes or no .

Bieber 's opponent benefits from each additional word Bieber says , because that 's part of another sentence the singer needs to testify consistently with at trial . We all know it 's nearly impossible to tell the same story twice , but a good cross-examiner will make minor inconsistencies from an earlier deposition look like a flawed memory , or worse , paint the witness as a liar .

In text form , sarcasm does n't read like sarcasm : Sarcasm is using words to indicate -LRB- sarcastically -RRB- the opposite of what you really want to say . Sarcasm really comes out in the way you say something .

Q : Did you shoot the sheriff ?

A : Oh yeah , sure . I shot the sheriff .

See ? Without the benefit of the voice and visual elements of sarcasm , on paper someone just admitted to shooting the sheriff , when maybe they wanted to be sarcastic . Devastating .

For the most part , you 're on your own : Bieber 's lawyer actively objected to protect his client , but deponents often feel like their lawyers are n't getting involved enough . For the most part , lawyers can not . The rules of discovery seriously limit how much Bieber 's attorney can object . He can object `` for the record , '' which means the judge can later decide if the answer is ultimately admissible at trial . Of course , some questions are so outside the realm of relevance or civility that the attorney has to intervene . The questions about Bieber 's personal relationships could potentially fall into this category , because they appear to stretch the boundaries .

It was n't all terrible : In fairness to Bieber , he did some things right . He made it clear when he did not understand a question . That 's critical , because if he answers a question without fully understanding it , the court will later on assume he understood it when he answered it . Bieber appears on the video to really think about the meaning of the questions and his answers . If he could carve out his other behavior , in some respects , he 's not half-bad as a deponent .

The opinions expressed in this commentary are solely those of Danny Cevallos .

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Danny Cevallos : Justin Bieber is petulant and sarcastic in a videotaped deposition

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Cevallos : Bieber should know this is not an interview : Interruptions just hurt his side

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Cevallos : Depositions are not soapboxes ; you are n't there to match wits and bicker

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Cevallos says all you say in a deposition is fodder for lawyers , so the less you say the better